A wide variety of electronic devices nowadays is provided with equipment for recording audio data. Examples for such electronic devices include portable electronic devices which are intended to simultaneously record audio and video data. Examples include modern portable communication devices or personal digital assistants. There is an increasing desire to configure such devices so as to allow a user to record audio data, possibly in combination with video data, originating from an object located at a distance from the electronic device.
Background noise may be a problem in many application scenarios. Such problems may be particularly difficult to address in cases where the electronic device is not a dedicated device for audio recording purposes, but has additional functionalities. In such cases, limited construction space as well as cost issues may impose constraints on which technologies may be implemented in the electronic device to address background noise problems.
Electronically controllable directional microphones provide one way to address some of the problems associated with background noise. For illustration, a directional microphone may be integrated into an electronic device which also has an optical system for recording video data. The directional microphone may be configured such that it has high sensitivity along the optical axis of the optical system. The directional microphone may also be adjusted so as to account for varying optical zooms, which may be indicative of varying distances of the sound source from the electronic device. In such an electronic device, the user will generally have to align the optical axis of the optical system with the sound source to obtain good signal to noise ratios. This may be inconvenient in some situations, and even close to impossible in other situations, such as when there are several sound sources in one image frame.
It is generally also possible to detect the direction in which sound sources are located based on the sound signals received at plural microphones of a microphone array. Based on time differences in arrival times of pronounced sound signals, the direction of at least the dominant sound source may be estimated. Relying on the output signals of a microphone array for controlling the audio recording may be undesirable for various reasons. For illustration, if the dominant sound source is different from the one the user is actually interested in, deriving a direction estimate based on the sound signals received at plural microphones may not allow the quality of sound recording to be enhanced for the desired sound source.